Screw viscosity pump



June 2, 1964 R. A. PETERSON l SCREW VISCOSITY PUMP Filed Jan. 25, 1965 United States Patent O 3,135,216 SEREW VSCSETY PUMP Rudolph A. Peterson, Rancho Cordova, Calif., assigner, by mesne assignments, te the United States of America as represented by the Secretary of the Navy Filed lan. 25, 1963, Ser. No. 254,323 1 Claim. (Cl. 10S-89) This invention relates to a pump for providing pressurized ow to propellants of high viscosity and which will not create pressure high enough to ignite the propellant.

1n the handling of semi-solid propellants, the ordinary pumping actions to maintain flow through pipes occasionally creates pressures which are sufliciently high to ignite the propellant. This propellant, which is of the consistency of bread dough or soft putty, must be discharged into the casting mold at a pressure suiciently high to ill all the interstices of the mold and to prevent the formation of voids within the body of the grain.

One object of the present invention is to provide a pump which will provide a pumping action to the propellant without creating pressures high enough to ignite the propellant.

It is another object of the invention to provide a pump for propellants having suiiicient pump slip so as to obviate the necessity for surge tanks located between the pumps and to permit the pumps to be used in series in propellant vpipelines without harmful effects.

It is a further object of the invention to provide a pump of the conveyor screw type which can be fabricated to any desired length and which can operate at a speed from very slow to 480 rpm. depending on the discharge pressure required.

It is a still further object of the invention to provide a pump of the screw type having a ight direction which varies from approximately 8 to 25 and which can be made in diameters from 1/4 inch to 2 feet.

Other objects and many of the intended advantages of this invention will be readily appreciated as the same becomes better understood with reference to the following detailed description when considered in connection with the accompanying drawings wherein: FIG. 1 is a longitudinal sectional view of the pump.

FIG. 2 is a section taken along line 2-2 of FIG. 1; and

FIG. 3 is a section taken along line 3--3 of FIG. 1.

Referring particularly to FIG. l, a base 11 is provided with upstanding members 12 and 13 which respectively house bearings 14 and 15. These bearings support the reduced portion of a cylindrical screw 17. The reduced portion 16 and an enlarged spindle portion 1S form the moving parts of the propellant pump. The spindle 1S is supported in a cantilever manner and is formed with a shallow helical flange 19 which may vary in angle from substantially 8 to` 25.

A cylindrical housing 21 is mounted on supports 22 and 23 of the base 11 and encloses the spindle portion of the screw. It is formed with an open discharge end 24, an inlet pipe opening 25, and a substantially closed end 26 through which the reduced portion 16 projects. This opening 26 is provided with a seal 27 to prevent the escape of any propellant delivered by a pipe 28 through the opening 25 to the interior of the housing.

The spindle 18 is formed with a ared end 29 extending from approximately the position of the inlet opening 25 to the closed end 26. This ared end is to urge the propellent in the direction of the open end 24 and to prevent undue friction at the closed end by reason of packing of the propellant at the end during the pumping operation. The spindle 18 is of comparatively large diameter while the flanges 19 are shallow and are maintained spaced from the inner wall of the housing throughout the length of the screw.

A pulley 31 provides a driving means for the pump through a belt and motor (not shown).

Operation of the pump conducts the propellant, which is fed through the pipe 28 and the housing, the length of the housing at pressures depending entirely `upon the speed at which the screw is rotated. The spacing of the helical ange from the housing and cantilever support of the screw provides slippage preventing undue friction which may possibly ignite the propellant.

From the above description of a specific embodiment of` the invention, it may be clearly seen that a pump, employing a screw of the conveyor type yet cantilever supported within a housing will handle propellants of a high viscosity without creating excessive friction suicient to ignite the propellant. This factor of safety permits the propellant to be handled at pressures which will avoid voids in the grain and which completely fills the irregularly shaped mold.

Obviously, many modications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claim, the invention may be practiced otherwise than as specifically described.

What is claimed is:

A screw pump for high viscosity uids comprising:

a support for said pump;

a cylindrical housing formed with a constant diameter cylindrical'bore, an open unobstructed discharge end and an oppositely closed end, said housing being mounted on said support;

a cantilever spindle rotatively mounted on said support, said spindle having a short frusto-conical portion and a long enlarged substantially cylindrical section extending within said housing so that no portion of the spindle touches the housing and terminating just short of said open discharge end;

a spiral impelling flange integral with said spindle and extending the full length of the frusto-conical portion and the enlarged cylindrical section, the ange being of comparative shallow depth and forming an impelling screw, the outer diameter of which is evenly spaced from the inner cylindrical bore of the housing throughout its length;

said housing being further formed with an inlet port adjacent the closed end where the frusto-conical portion and the cylindrical section merge, the area of the inlet port being less than the area of the discharge end, the spiral impelling flange increasing in depth from the end adjacent the closed end of the housing to the end of the frusto-conical portion of the spindle and then remaining of constant depth over the entire cylindrical portion of the spindle.

References Cited in the tile of this patent UNITED STATES PATENTS I 482,655 Schetzel Sept. 13, 1892 917,206 Watts Apr. 6, 1909 1,067,980 Stewart July 15, 1913 2,673,523 Larson Mar. 30, 1954 2,805,627 Bendett et al. Sept. l0, 1957 2,877,710 Barnhart Mar. 17, 1959 FOREIGN PATENTS 50.022 France oet. 1, 1939 1,064,526 France Dec. 23, 1953 295,999 Italy Mar. 6, 1932 328,298 Italy Aug. 3, 1935 

